Seat head rests have been used for many years in automotive vehicles. These head rests generally extend vertically from the seat back and may prevent neck hyperextension. For optimum effectiveness, such head rests must be adjusted properly. Frequently, however, the seat occupant incorrectly adjusts the height of the headrest, often making the position choice for reasons of comfort only.
Complicating the proper positioning of the head rest relative to the seat back is the fact that many automotive vehicles today are configured so that one or more seat backs may be folded flat or relatively flat against the seat base, thereby allowing the back of the seat back to be used as storage space for packages. Often the head rest interferes with proper movement of the seat back from its upright position to its lowered position when the operator is arranging the seat for package storage. The head rest is then moved to its lowered position and in some instances it remains in its lowered position when the seat back is returned to its upright position for occupant seating. The lowered position may not be optimum for passenger safety.
A further complication relates to the anticipated requirement for taller head rest positions than current products can provide. However, this greater fixed height often precludes existing seat designs from other functions such as the above-described seat back lowering for use in storing packages, or an inability to meet the height requirement without relying on the customer to adjust the position of the head rest.
Accordingly, what is desired is a system that fixes the head restraint at the taller required height when a passenger is sitting in the seat, prevents the passenger from adjusting the head restraint height while sifting in the seat, and which retracts the head restraint automatically when the user lowers the seat back thereby providing sufficient package clearances. Known systems are not capable of simultaneously achieving both the height degree anticipated to be required for proper operation of a seat assembly and the capability of moving from an upright position to a lowered position.